i6o The Irish NaUcralist. August, 



NOTES. 



BOTANY. 



The New Flora of the Burnt Ground on the Hill of Howth. 



INIr. Adauis' short article on this sul)ject iu the last number of the Irish 

 Naturalist is verj' interesting, but I think it is open to question whether it 

 might not have been perhaps more appropriately entitled a study of 

 survival rather than one of dispersal. It must be remembered that 

 although, as stated, the fire smouldered for over a week, it was largely 

 spreading at its edges during this time, and probably no one patch of 

 ground was involved in actual fire for anything like this whole period. 

 On the contrary, I imagine that here and there the period of actual 

 burning may have been a very short one indeed. I think it quite possible 

 that seeds of the majorit}- of plants mentioned in the list given survived 

 the fire, and that, therefore, there is no need to seek for methods by which 

 the)' may have subsequently arrived there. Particularly is this the case 

 with the Whin. I have often seen seedlings of this plant coming up in 

 hundreds beneath comparatively recentl}- burned bushes. The ver)- 

 large numbers in which they occur point surely to the fact that the 

 seeds, having previously fallen in quantities from the plants, survived 

 the fire. Had they arrived afterwards would not their numbers have 

 been far less ? Similarly, when the heather}- vegetation is burned on 

 our moorlands, the regeneration occurs, surely much faster than it 

 would do if it depended only on seeds transported subsequently from 

 without the area ? I do not think a close parallel can be drawn between 

 this instance and that of Krakatoa, for in the latter case the whole 

 vegetation of the island was blotted out by a mantle of red hot lava and 

 ash, and the effect of the fire at Howth cannot possibly have been any- 

 thing like so severe as this. 



With regard to the species of plants occurring after the fire, repre- 

 sentatives of the great majority' of them were certainly there before it 

 occurred, though perhaps the two Epilobiums, Senccio vulgaris, and Souihus 

 olcraceus amongst others may be exceptions. The most striking absentee 

 is certainly Vlex Gallii ; I am not sure whether in the seedling stage this 

 can readily be distinguished from U. europicus. and if not I rather expect 

 that some of the seedlings put down as the latter may really belong to 

 the former species. I am inclined to believe that seeds of most of the 

 plants named were lying in plenty, more or less burned, when the fire 

 took place, and that very many of them survived it. If so they would 

 probabh- have germinated in the following season. Mr. Adams' list was 

 made three years after the fire, and if this was the first season in which 

 plants were to be observed at all on the burned area possibly they were 

 derived from seeds carried there subsequent!}-. It would be interesting 

 to know if anyone visited the area the season next following the fire, and 

 if seedling plants were observed then and in what numbers. 



Geo. H. Pkthvbridge. 

 Royal College of vScience, Dublin. 



